Urban Heat Island

• Introduction
• The Phenomenon of Urban Heat Island
• Causes and Effects of UHI
• Mitigation Efforts
• Urban Heat Island (UHI) of Urban Cities of United States • UHI and Climate Trends of Some Major cities of US
• Urban Heat Island (UHI) Mitigation Strategies in United States • Conclusion

Urban Heat Islands
Introduction Urban Heat Island – UHI is one of the important phenomenons of meteorology. It refers to a metropolitan area that becomes significantly warmer as compared with the areas surrounding it. Urban heat island is a well-documented and widely accepted outcome of the human modifications to the environment. The temperature of the metropolitan area differs from those surrounding areas mostly at night time, especially in summer, and during the dry clear, and calm weather when there is flow of weaker winds. The urban heat islands draw some very significant atmospheric, biological, and economic impacts that strongly affect the human life in most of the urban areas (Runnalls and Oke, p283). The paper discusses the phenomenon of the urban heat island in general as well as specifically in relation to some major cities of United States including cities of New York and New Jersey. In this regard, the paper traces the evolution of the phenomenon of the urban heat islands and discusses the major causes that led towards the occurrence of urban heat islands. The potential effects of the urban heat inland are also discussed in this paper along with the mitigation measures that can be taken to reduce the increasing temperature of the urban heat islands. Furthermore, the paper discusses the existence of urban heat island specifically in New York, New Jersey and the surrounding cities of the United States and it also compares the temperature of the region with the temperature of the surrounding areas. The socio-economic effects of urban heat islands and the measures taken by the US government to reduce the harmful effect of urban heat island in the region are also highlighted.

The Phenomenon of Urban Heat Island

The phenomenon of urban heat island is basically characterized by the human induced landscape changes that resulted in the creation of differences between the urban and rural environment temperatures. These mitigation measures not only help in keeping the temperature of the urban at lower levels but also protect the human health from the negative consequences of the urban heat islands by reducing air pollution. The concept of urban heat island is not very new and soon after the trend of urbanization got momentum, the experts noticed the difference between the temperature of the urban areas and their surroundings. Luke Howard in the mid nineteenth century discovered that London was warmer then the surrounding countryside and that this temperature difference are contributed by the human activities that bring changes in the environment (Renou, p105). After this discovery, the urban heat islands became an important area of meteorological studies and the experts started paying close attention towards discovering and identifying the climatic impacts of the human activities that result in the rise of the temperature of the urban areas. The researchers (e.g. Runnalls and Oke, p283; Oke and Maxwell, p191) discovered that the magnitude of the urban heat island is heavily dependent upon the synoptic meteorological parameters including cloud cover, wind speed and generalized synoptic weather regimes and the urban heat island are among the major outcomes of the human induced modifications that change the environment and climate. (Runnalls and Oke, p283) Most of the early studies of this phenomenon on the urban heat islands discovered that the urban heat islands occur mostly in dry, clear, and calm nights, and they usually occur near the center of anticyclones[1]....

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